• Toxicological Research
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• v.19 no.3
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• pp.227-234
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• 2003

2-Bromopropane (2-BP), a halogenated propane analogue, is a substitute for chlorofluorocarbones (CFCs) which have a great potential to destroy the ozone layer and to warm the earth's environment. The present study was undertaken to evaluate the potential adverse effects of 2-BP on pregnant dams and embryo-fetal development after maternal exposure during the gestational days (GD) 6 through 17 in ICR mice. The test chemical was administered subcutaneously to pregnant mice at dose levels of 0, 313, 625 or 1,250 mg/kg/day. All dams were subjected to caesarean section on GD 18 and their fetuses were examined for external, visceral and skeletal abnormalities. In the 1,250 mg/kg group, maternal toxicity included an increase in the incidence of abnormal clinical signs and a decrease in the maternal body weight, body weight gain, and corrected body weight. Developmental toxicity included a decrease in the fetal body weight, a reduction in the placental weight, an increase in the fetal skeletal variation and ossification delay. There were no adverse effects on either pregnant dams or embryo-fetal development in the 313 and 625 mg/kg groups. These results suggest that a 12-day subcutaneous dose of 2-BP is embryotoxic at a maternally toxic dose (i.e., 1,250 mg/kg/day) in ICR mice. In the present experimental condition, the no-observed-adverse-effect level of 2-BP is considered to be 625 mg/kg/day for dams and embryo-fetuses, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.207-218
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• 2013

One of the input parameters in the evaluation of seismic performance of rockfill dams is shear-wave velocity of rock debris and clay core. Reliable evaluation of shear-wave velocity by surface-wave methods requires overcoming the problems of rock-debris discontinuity, material inhomogeneity and sloping boundary. In this paper, for the shear-wave velocity investigation of rockfill dams, SBF (Short-Array Beamforming) technique was proposed using the principles of conventional beamforming technique and adopted to solve limitations of the conventional surface-wave techniques. SBF technique utilizes a 3- to 9-m long measurement array and a far-field source, which allowed the technique to eliminate problems of near-field effects and investigate local anomalies. This paper describes the procedure to investigate shear-wave velocity profile of rockfill dams by SBF technique and IRF (Impulse-response filtration) technique with accuracy and reliability. Validity of the proposed SBF technique was verified by comparisons with downhole tests and CapSASW (Common-Array-Profiling Spectral-Analysis-of-Surface-Waves) tests at a railroad embankment compacted with rock debris.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.9-15
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• 2019

Rainfall patterns are changing due to climate change, the frequency of drought occurrence is shortening, and the operation of the multi-purpose dams is also changing. The importance of preventing water shortage of multi-purpose dams in advance and operation for stable water supply is increasing. In this study, we developed and evaluated the operational criteria reflecting climate change scenarios based on the operational criteria currently applied to multi-purpose dams. Standard water volume lines reflecting climate change were found to increase 34% on average, as a result of evaluation with the existing standard, it was analyzed that water supply would not be difficult if the multi-purpose dam operation standard reflecting climate change was applied. The results of this study are expected to be helpful for the establishment of multi-purpose dams reflecting climate change.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.149-162
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• 2001

Longitudinal cracks have occurred on the crest of dams soon after their construction of two earth-rocfill dams located in Samlangjin. They are a pair of pumped storage dams constructed for generation of electrical power. The upper dam and lower dam are subjected to the variation of water level more than 10m once in a day alteratively. This paper deals with the finding of possible causes for longitudinal cracks about upper dam. The dominant cause was considered to be due to fluctuation of water load, for which numerical analysis was carried out using the hyperbolic model. In order to obtain parameters necessary to the analysis, a series of triaxial tests was performed for both core and rock material. Also dynamic triaxial test was performed to obtain dynamic properties of soils, which could be used as input data to simulate frequent variation of stress change due to the water fluctuation. It was known from the numerical analysis that the confining pressure of upper 4m from the top of the crest become negative after repeating of water load, meaning that tension cracks occurred in the top portion of the crest. The depth of longitudinal cracks has been investigated by digging test pit on the crest. This results agree with the field observation.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.569-577
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• 1996

This study was performed to determine the effect of maternal protein intake on 1) the concentration of immune substances in milk 2) degree of passive immunity to pups via lactation, and 3) specific antibody production to a specific antigen, $\beta$-lactoglobulin(BLG). 4) the effect of passive immunity that pups received from mother during lactation on the production of antibodies when the pups were challenged to the same antigen. Part of the female rats were immunized with BLG before and during pregnancy. The pregnant rats were placed into either 25% or 10% isolated soy protein diet throughout gestation and lactation. After weaning, pups from each group continued to be fed the same diet. At 18 weeks of age, all the pups were challenged with BLG. Total IgA and IgG, lysozyme, BLG-specific IgA and IgG were measured in dam's serum, dam's milk, and pup's serum. Total IgG, and lysozyme in dam's serum and milk were higher in high protein group. Total IgA and IgG in pup's serum remained higher in high protein group from 5 to 18 weeks of age. BLG-specific antibodies were found in the milk and serum of immunized dams, and in serum of pups born to immunized dams but not in the non-immunized group. BLG-specific IgA and IgG were again higher in high protein group and declined with time. The concentration decreased faster in the low proetein group than in the high protein groups. After immunization the pups with LBG, serum BLG-specific antibodies were not differ between rats born to immunized dams and those born to non-immunized dams. Therefore passive immunity rats received via milk as a pup had no effect on the BLG-specific antibody production later in life. This study shows the importance of protein status of mother and strongly support to the endorsement of breast feeding.

• Computers and Concrete
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• v.20 no.3
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• pp.275-282
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• 2017

Grouting is an operation often carried out to consolidate and seal the rock mass in dam sites and tunnels. One of the important parameters in this operation is grouting pressure. In this paper, analytical models used to estimate pressure are investigated. To validate these models, grouting data obtained from Seymareh and Aghbolagh dams were used. Calculations showed that P-3 model from Groundy and P-25 model obtained from the results of grouting in Iran yield the most accurate predictions of the pressure and measurement errors compared to the real values in P-25 model in this dams are 12 and 14.33 Percent and in p-3 model are 12.25 and 16.66 respectively. Also, SPSS software was applied to define the optimum relation for pressure estimation. The results showed a high correlation between the pressure with the depth of the section, the amount of water take, rock quality degree and grout volume, so that the square of the multiple correlation coefficient among the parameters in this dams were 0.932 and 0.864, respectively. This indicates that regression results can be used to predict the amount of pressure. Eventually, the relationship between the parameters was obtained with the correlation coefficient equal to 0.916 based on the data from both dams generally and shows that there is a desirable correlation between the parameters. The outputs of the program led to the multiple linear regression equation of P=0.403 Depth+0.013 RQD+0.011 LU-0.109 V+0.31 that can be used in estimating the pressure.

• Earthquakes and Structures
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• v.18 no.2
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• pp.201-213
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• 2020

Seismic damages that occurred by the effects of epicenter distance of the earthquake are one of the most important problems for the earthquake engineering. In this study, it is aimed to examine the nonlinear seismic behaviors of concrete gravity (CG) dams considering various epicenter distances. For this purpose, Boyabat CG dam that is one of the biggest concrete gravity dams in Turkey is selected as a numerical application. FLAC3D software based on finite difference method is used for modelling and analyzing of the dam. Drucker-Prager nonlinear material model is used for the concrete body and Mohr-Coulomb nonlinear material model is taken into account for the foundation. Special interface elements are used between dam body and foundation to represent interaction condition. Free-field and quiet non-reflecting boundary conditions are utilized for the main surfaces of 3D model. Total 5 various epicenter distances of 1989 Loma Prieta earthquake are considered in 3D earthquake analyses and these distances are 5 km, 11 km, 24 km, 85 km and 93 km, respectively. According to 3D seismic results, x-y-z displacements, principal stresses and shear strain failures of the dam are evaluated in detail. It is clearly seen from this study that the nonlinear seismic behaviors of the CG dams change depending to epicenter distance of the earthquake. Thus, it is clearly recommended in this study that when a CG dam is modelled or analyzed, distance of the earthquake fault to the dam should be strongly examined in detail. Otherwise, earthquake damages can be occurred in the concrete dam body by the effects of seismic loads.

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05a
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• pp.219-225
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• 2003

The World Commission on Dams (WCD) in November 2000 published "Dams and Development" as its only and final report. The report proposed "internationally acceptable criteria and standards" Despite the (act that the WCD itself did not regard the report as a blue print, many NGO's strongly support the report and the guidelines, and demand that they be adopted in their current form by funding organizations. The WCD recommendations and guidelines were found to have several "generic" problems, and the proposed guidelines appear unable to be applied as they stand. The authors assume that only several of these guidelines are operational and many of these are either too experimental or theoretical to be put into use. Furthermore, some seemingly "ready for operation" guidelines still need to be enhanced to be really operational in the real world. About 2,000 large dams were constructed in Japan after the Second World War. Various principles and mechanisms were then developed to better address the issues related to involuntary resettlement. The knowledge accumulated through large dam construction projects in Japan may be applied to other countries. The aim of this paper is to identify the lessons, out of the experiences gained in Japan through large dam construction projects in the past, which could be applicable for future large dam construction projects in other nations. The socio-economic settings as well as legal frameworks in Japan may differ other nation. Nevertheless, the following aspects of the experiences gained in Japan are found to be both applicable and useful for future large dam construction projects abroad: (a) Integrity of community in the negotiation process, (b) Provision of alternative occupations, (c) Funding mechanism in the post-project period, (d) Measures needed during planning process, and (e) Making resettlers "shareholders". These lessons may prove useful to enhance the WCD guidelines.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.61-70
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• 2003

The behaviour of an earth and rock-fill dam is complicated due to reservoir water and various materials in zoned dams. Different materials with a wide range of permeability and seasonal variation of reservoir water result in the time dependent post-constructional behaviour. In aged dams it is often required to control water level to keep the dams safe. In this case information on the post-constructional dam behaviour is important. However, present geotechnical knowledge does not fully support the occasion. In this study the post-constructional behaviour of a dam is investigated using coupled finite element models for series of idealized water reservoir cases: impoundment, draw down, seasonal fluctuation with different rising and falling speeds. Numerical results were analysed in respect of geotechnical parameters such as load transfer, hydraulic fracturing potential and stress paths. It is shown that the control of water level is an important factor while operating dams.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.435-439
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• 2000

Records of weight, age, body condition at calving and udder characteristics scores of 425 beef cows and birth weights and periodical weights of their offspring from birth to weaning were analyzed to study the effect of body weight, condition and udder characteristic scores of dams on birth weight and Preweaning growth of their offspring. Dam's body condition (fat reserve) at calving were scored on a scale of 1 to 5 (1=extremely thin and 5=extremely fat) and dam's udder characteristics were scored on a scale of 1 to 7 (l=udder well attached with small teats and 7=at least one quarters not functional). Dams were from three distinct breed groups and were mated in single sire mating groups within each breed group for 45 days. Within each breed group and year, the dams were classified into high, medium and low based on their weights at the time of parturition. The data were analysed using covariance analysis. In general, calves born to heavier dams were heavier at birth and had higher rate of Preweaning growth. The effect of dam's body condition score on the calf birth weight was not significant. However, cows with average body condition score of 2.5 or 3.0 gave birth to calves that had higher pre weaning growth rates up to weaning than those born to calves with higher body condition score. The udder characteristics score did not affect calf birth weight as expected; however, cows with udder score of 3 (udder well attached with large teats) produced calves with higher preweaning growth rate than those with smaller teats. Based on the results, it can be concluded that maintaining animals with average body condition and weight would result in more efficient calf production. In addition, cows with well attached udder and large teats would provide a better maternal environment for Preweaning growth rates of their calves.